Holden HQ HJ HX HZ WB 5.7L 6.0L 6.2L LS V8 Conversion Pacemaker Headers PH5342

Pacemaker PH5342 headers (extractors) are specifically designed for Holden HQ, HJ, HX, HZ and WB LS V8 engine conversions.

Pacemaker lists PH5342 for 5.7L, 6.0L and 6.2L LS-family V8 engines. This covers commonly used conversion engines including the LS1, LS2 and LS3, along with other compatible 6.0L LS-family combinations where the conversion configuration is suitable.

The tuned 4-into-1 design uses 44mm (1¾") primary pipes and large 76mm (3") outlets, providing a performance-oriented header package specifically designed for installing an LS V8 into the classic Holden HQ-WB chassis.

IMPORTANT – LS conversions can vary depending on engine mounts, sump, steering, starter motor, transmission and engine position. Confirm your individual conversion configuration before ordering.

Please check availability and current lead time before ordering.

Key Features

• Tuned 4-into-1 header design
• 44mm (1¾") primary pipes
• 76mm (3") outlets
• Designed specifically for HQ-WB LS V8 engine conversions
• Suits 5.7L, 6.0L and 6.2L LS-family V8 engines
• Manual and automatic transmission compatible
• Power steering compatible
• Air conditioning compatible
• Oxygen sensor provisions incorporated into the headers

Construction

Pacemaker PH5342 uses a tuned 4-into-1 configuration with 44mm (1¾") primary pipes feeding into large 76mm (3") outlets.

The design is specifically configured for installing an LS-family V8 into the Holden HQ-WB chassis while retaining compatibility with power steering and air conditioning.

Additional Options

Ceramic Coating: PHC40 ceramic coating may be available for improved heat management and corrosion resistance. Please contact Best Mufflers for current availability.

DSF138: Replacement LS exhaust manifold/header gaskets are available separately.

Vehicle Fitment

• Holden HQ: LS V8 conversion
• Holden HJ: LS V8 conversion
• Holden HX: LS V8 conversion
• Holden HZ: LS V8 conversion
• Holden WB: LS V8 conversion
• Engine Capacity: 5.7L / 6.0L / 6.2L LS-family V8
• Common Engines: LS1 / LS2 / LS3 and compatible LS-family applications
• Transmission: Manual / Automatic
• Drive: Rear-Wheel Drive
• Power Steering: Yes
• Air Conditioning: Yes

Pacemaker lists PH5342 as an HQ-WB LS V8 conversion header. These engines were not factory fitted to HQ-WB models, so vehicle year references relate to the chassis rather than the LS engine.

Header Specifications

• Part Number: PH5342 L/R
• Brand: Pacemaker
• Design: Tuned 4-into-1
• Primary Pipe: 44mm (1¾")
• Secondary Pipe: N/A
• Outlet: 76mm (3")
• Power Steering: Yes
• Air Conditioning: Yes
• Oxygen Sensor: Yes
• EGR: N/A
• Replacement Gasket: DSF138
• Approximate Fitting Time: 2 hours

Fitment Notes

LS Conversion: PH5342 is specifically designed as an LS V8 conversion header for the Holden HQ-WB chassis.

Engine Capacity: Pacemaker specifies 5.7L, 6.0L and 6.2L LS-family V8 engines.

Transmission: Suitable for manual and automatic transmissions.

Power Steering: Pacemaker lists PH5342 as power-steering compatible.

Air Conditioning: Pacemaker lists PH5342 as air-conditioning compatible.

Oxygen Sensors: PH5342 incorporates oxygen sensor provisions for LS engine management systems. Oxygen sensor wiring position should be checked during installation and may require adjustment or extension depending on the conversion wiring layout.

Engine Mounts: Engine position is critical in an LS conversion. Engine mounts, sump configuration and associated conversion components can affect header clearance. Confirm that the mounting system being used is compatible with PH5342 before ordering.

Check clearance around the steering, starter motor, transmission, chassis rails, floor and other conversion components during trial fitting.

Protect painted surfaces during trial fitting and do not fully tighten the headers until all required clearances have been confirmed.

What's Included

• Pacemaker PH5342 left-side header assembly
• Pacemaker PH5342 right-side header assembly

Do not assume header bolts, gaskets or other installation hardware are included unless confirmed with the current kit before ordering.

Recommended With

• DSF138 LS exhaust manifold/header gaskets
• Suitable LS conversion engine mounts
• Suitable 3" intermediate pipes, joiners or exhaust adaptors
• Professional exhaust system fabrication where required

PH5342 vs PH5343

PH5342: Tuned 4-into-1 design with 44mm (1¾") primary pipes and 76mm (3") outlets.

PH5343: Competition 4-into-1 design with larger 48mm (1⅞") primary pipes and 76mm (3") outlets.

Both are designed for HQ-WB LS V8 conversions and Pacemaker lists both for 5.7L, 6.0L and 6.2L applications. PH5343 provides the larger primary pipe option for higher-output combinations.

Why Good Headers & Exhaust Systems Matter

At 4,000 rpm, a 5.7L LS V8 theoretically draws approximately 11,400 litres of intake air per minute at 100% volumetric efficiency and expels around 34,200 litres of hot exhaust gas per minute at approximately 600°C.

A 6.0L LS V8 theoretically draws approximately 12,000 litres of intake air per minute, while a 6.2L LS V8 theoretically draws approximately 12,400 litres per minute at the same engine speed. The corresponding illustrative hot exhaust volumes are approximately 36,000 and 37,200 litres per minute.

Actual airflow varies with engine capacity, RPM, volumetric efficiency, camshaft, cylinder heads, induction system and engine specification.

A well-designed header and exhaust system helps manage this high gas flow efficiently, reducing restriction and improving exhaust scavenging, torque, throttle response and engine performance.

Installation Tips

LS engine conversions can vary considerably. Before installation, confirm the engine mounts, sump, steering system, starter motor position, transmission and engine position used in the vehicle.

Trial fit both headers before completing the downstream exhaust system and check oxygen sensor positioning and wiring clearance.

Because PH5342 uses 3" outlets, the downstream exhaust system will need to be configured appropriately.

Professional installation is recommended, particularly where the vehicle requires fabrication or engineering approval as part of the LS conversion.

Warranty & Compliance

Pacemaker headers are covered against manufacturing defects subject to Pacemaker's current warranty terms and conditions.

Because PH5342 is intended for an engine conversion, the completed vehicle must comply with applicable Australian state or territory requirements relating to engine conversions, emissions, exhaust noise and vehicle modifications.

FAQ

What vehicles do PH5342 headers suit?
PH5342 is designed for Holden HQ, HJ, HX, HZ and WB LS V8 engine conversions.

What engines do PH5342 headers suit?
Pacemaker specifies 5.7L, 6.0L and 6.2L LS-family V8 engines, including commonly used LS1, LS2 and LS3 conversion applications.

Are PH5342 headers Tri-Y?
No. PH5342 uses a tuned 4-into-1 design.

What size are PH5342 headers?
They use 44mm (1¾") primary pipes and 76mm (3") outlets.

Will PH5342 fit an LS1?
Yes. The 5.7L LS1 is a principal PH5342 conversion application.

Will PH5342 fit an LS2?
Yes. Pacemaker lists 6.0L LS-family applications for PH5342.

Will PH5342 fit an LS3?
Yes. Pacemaker lists the 6.2L LS application and identifies PH5342 as suitable for LS3 engine conversions.

Will PH5342 fit with air conditioning?
Yes. Pacemaker lists PH5342 as air-conditioning compatible.

Will PH5342 fit with power steering?
Yes. Pacemaker lists PH5342 as power-steering compatible.

Does PH5342 have oxygen sensor provisions?
Yes. Pacemaker specifies oxygen sensor provision for PH5342.

What gasket suits PH5342?
Pacemaker specifies DSF138.

What is the difference between PH5342 and PH5343?
Both are 4-into-1 HQ-WB LS conversion headers with 3" outlets. PH5342 uses 44mm (1¾") primaries, while the PH5343 Competition header uses larger 48mm (1⅞") primaries.

Can I pick up from the store?
Yes. Pick up is available but must be pre-arranged before collection.

How much is freight?
Freight varies depending on your delivery location and where stock is available. Please contact us for freight charges before ordering. Where possible, we can arrange dispatch from the nearest available product location to help reduce freight costs and delivery times.

Do you ship to the USA?
Yes. Best Mufflers regularly ships exhaust systems and exhaust parts to customers throughout the United States.

Please note that import duties, tariffs, taxes, and customs clearance fees are not included in the product or shipping price. Once your order is processed and the applicable charges are calculated, we will send you a secure payment link to finalise the import duties and tariff charges before dispatch.

Customer Support

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